Converting 1440x1080 to 1920x1080 Properly?

I'm on a project that's thinking about shooting with a HVX-200 in AVC-50 for budget reasons. This will produce video that's 1440x1080 HD. That size is fine for what we're already confirmed for, but our producer hopes to get the project syndicated to local, commercial stations. Some of those stations broadcast in 1920x1080.

I read somewhere that I can edit this image size in 1920x1080 and everything would look fine. I'm assuming to export I would have to specify that I want the image size to be 1920x1080. Is that the best way to change the size and preserve as much quality as possible? If not, what's the best way? From what I've read, conversion will change the pixel size from non-square to square. I'm hoping proper conversion won't make everything look badly stretched out and everyone 10 pounds heavier. How bad is the stretch?

I have to talk to my producer this week so any information you can give would be greatly appreciated.

[Kristyn Davis]"I read somewhere that I can edit this image size in 1920x1080 and everything would look fine. I'm assuming to export I would have to specify that I want the image size to be 1920x1080. Is that the best way to change the size and preserve as much quality as possible?"
Edit on a 1920x1080 Square pixels sequence and export a QT movie (no QT Conversion).
That's all.
You can also edit and export 1440x1080 and upscale in Compressor, with "Frame Control ON" to 1920x1080 Squared pixels.
rafael

The 50 in DVCPro 50 stands for 50 mb/sec, and so does the 50 in AVC-Intra 50. The problem: one is SD and the other is HD.

I realize compression keeps getting better at preserving image quality, but FCP 7's never been known to play nice with interframe compression. How many people have ended up going back to Square One with H.264 in FCP 7?

If the edit application was X or Avid or Premiere Pro that's fine, but we're talking FCP7.